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I have this article which is not clear to me.

And also someone told me that swap space does not need to be disable if it is before the partition to resize.

Modifications: This is the related question extend size of partition. I am resizing a partition to add the extra/unallocated 1500GB disk space on the same disk. And would be better not to do it with lvm if possible.

I hope someone would enlighten me. Thanks

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If I were you I would build a VM and try the commands in a VM first. – Zoredache Nov 19 '12 at 16:47

Line one of the linked article is pretty clear to me:

Do not attempt to resize a partition on a device that is in use.

I think that makes it fairly clear that the CentOS wiki feels it needs to be unmounted ( in addition, the instructions recommend that you boot to rescue mode, which will effectively unmount all the partitions).

Edit: I understand from your other question that you propose to extend /dev/sda3, which is your root partition (which is, incidentally, where the OS is). As I understand it, online positive resizing (ie, resizing to expand a partition, without unmounting it) is supported for ext3 filesystems, but if you're going to try that, make sure you have excellent backups first, and that you've tested and documented your restore procedure.

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Thanks @MadHatter. So there is no way for me to resize without booting from rescue mode? In my situation I do not have the physical access to the server. I just want want to do the resizing instead of having the support just to avoid additional fee. Thanks – Jan Mark Nov 19 '12 at 12:48
If you can unmount the partition, that should suffice - but if it's your root partition, I think you'd be fairly insane to try it with the OS running. – MadHatter Nov 19 '12 at 13:09
Thanks @MadHatter we had the os and root in different partitions. Can I unmount it then and resize? – Jan Mark Nov 19 '12 at 13:13
I don't understand what you mean by "the OS and root in different partitions". Could you perhaps do a df -h, paste the results into your question, and say which partition you want to resize? – MadHatter Nov 19 '12 at 13:15
Here is the link to the details I have it a related question. Thanks @MadHatter. – Jan Mark Nov 19 '12 at 13:34

Yes, boot from the CentOS Live CD and select the rescue option, here is a full guide:

You really need to explain your questions better, you did not specify what type of partition you are resizing etc.

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